Antenna circuit



Patented Sept. 11, 1934 UNITED STATES ANTENNA CIRCUIT Harold H. Timian, Orion, Mich, assignor, by mesne assignments, to Radio Corporation of America, New York, Delaware Application March 18,

4 Claims.

This invention relates to a radio receiver mounted in a motor vehicle and in more particular to the antenna circuit of the radio receiver.

In mounting radio receivers upon motor vehicles, it is the general practice to use pick-up means or aerials that are mountedin the top or any other suitable place and to ground the circuit of the radio receiver to the car frame which functions as a counterpoise in the antenna circuit. The radio set is generally placed intermediate the aerial and the counterpoise.

As is well known to those skilled in the art, motor vehicle construction involves a chassis supporting the body, engine and incidental units for propulsion. To provide easy riding, the chassis includes springs that are interposed between the frame supporting the body and the axles, all of which are made from metallic parts. These springs provide means of movement between the car body and the axles. In order to provide a smooth movement these springs are usually oiled, which results in a poor electrical contact between the body and frame and the axles of the car. If the body of the car is used as a counterpoise for the antenna circuit of a radio receiver it can be readily seen that the electrical constants or the electrical properties of the counterpoise will vary depending upon the contact formed between the several metallic parts. If these metallic parts do not have a positive electrical connection any relative movement between the parts will function much the same as the adjustment of a variable condenser that results in undesirable disturbances being set up in the radio receiver.

An object of this invention is to provide a counterpoise for the antenna circuit that has substantially the same electrical properties at all times. This has been accomplished by providing positive electrical connections between the several metallic parts whereby the metallic parts function as a counterpoise composed of a single unit.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing wherein a preferred embodiment of one form of the present invention is clearly shown.

In the drawing:

In the single figure the reference character 10 indicates a radio receiver mounted in a motor vehicle 12. In the preferred embodiment the radio receiver 10 has been mounted beneath the cowl 14. The location of the radio receiver, however, is not material to this invention. The radio receiver 10 has been provided with an aerial 16 mounted in the top 13 of a car or any other suitable place such as underneath the car. The counterpoise of the radio receiver includes the metal- N. Y., a corporation of 1931, Serial No. 523,469

lic parts of the car. It is desirable that all of the metallic parts, especially the metallic parts that have a relative movement to each other, be connected by positive connections in order to eliminate or reduce noise caused thereby in the radio receiver. Whenever these parts are of different potentials and whenever the relatively movable metallic parts are not connected by positive electrical connections and are not completely shielded from the electric circuit in the radio receiver, movement between these electrical parts will function much the same as though a variable condenser were adjusted. This has. been overcome by providing positive electrical connections indicated schematically by the conductors 20 and 22 in the drawing. These conductorsmay either be welded to the metallic parts or joined thereto in any suitable manner.

While the form of embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. A counterpoise for a radio receiver mounted on a motor vehicle, said counterpoise including the relatively movable metallic body parts and axle of said motor vehicle, said metallic parts and.

axle having positive electrical connections so that the counterpoise has substantially the same electrical properties at all times.

2. A counterpoise for a radio receiver mounted on a motor vehicle, said counterpoise including the metallic body of the motor vehicle and the metallic running gear of said vehicle, and positive electrical connections connecting the body and the running gear into one electrical unit so as to reduce the variations in the electrical properties of said counterpoise.

3. In a radio equipped automotive vehicle having a metallic body movably suspended upon the metallic running gear, the combination comprising, a counterpoise for said radio installation including the metallic body of the vehicle, means bonding the composite unit of the body into an integral electrical unit, and means providing a positive electrical connection between the body and running gear irrespective of the movable relation of said body and running gear.

4. In a radio equipped automotive vehicle having a metallic running gear and a metallic body spring suspended thereon, a counterpoise comprising the said body and running gear and means providing. a positive electrical connection between said body and running gear, and means electrically joining a component part of said body and said running gear, both of said means reducing the metallic parts of said body and vehicle into an electrically joined unit.

HAROLD H. TIMIAN. 

